a(n) = (1/n) * Sum_{k=0..n-1} (8k+5) T_k^2, where T_0, T_1, ... are central trinomial coefficients given by A002426.
A179100
a(n) = (1/n) * Sum_{k=0..n-1} (8k+5) T_k^2, where T_0, T_1, ... are central trinomial coefficients given by A002426.
Terms
- a(0) =5a(1) =9a(2) =69a(3) =407a(4) =2997a(5) =22005a(6) =169389a(7) =1325889a(8) =10573677a(9) =85386881a(10) =697013325a(11) =5739021051a(12) =47599593941a(13) =397234035333
External references
- oeis: A179100